First Degree AV Block

A first degree AV block (also commonly refered to as a first degree heart block) is when there is a minor conduction blockage, that causes the time between the SA node firing and the AV node receiving an impulse to be longer in duration. It is a common dysrhythmia and occurs naturally in very fit people.

First Degree AV Block ECG

Heart Rate: usually mildly slower than normal.

Rhythm: Essentially regular

Pacemaker Site: SA Node

P-waves: normal.

PR Interval: prolonged duration (greater than 0.20 seconds)

QRS Complex: normal.

First Degree Heart Block Signs and Symptoms

These patients are usually asymptomatic.